1. Field of the Invention
This invention relates generally to the field of electrical or fiber-optic connectors possessing moisture and water proof integrity. More specifically, this application relates to connectors with additional features that facilitate ease of orientation and mating and result in a redundant seal.
2. Description of the Prior Art
As a preface, it should be noted that “male” and “female” designations for electrical connectors are not used consistently in the field. Some connectors are designated as “male” because their inserts are received into the shells of the mating connectors, regardless of whether their electrical contacts are sockets, pins (or blades, etc.), or a combination of sockets and pins. (“Insert,” as used herein, designates that part of the connector which holds the contacts in position and electrically insulates them from each other and from the shell. The insert need not be a separate removable component of a connector assembly, as is the case with many cylindrical connector assemblies, and it may include the portion of a bonded unitary connector which performs the same function. The “shell” designates the outside case or outer surface of the connector.) Other connectors (e.g. D-subminiture connectors) are designated as “male” because their pin contacts are received into the socket contacts of the mating connectors, regardless of the fact that the shells of the male connectors receive the inserts of the female connectors. Furthermore, a connector pair may be arranged with no shell overhang so that neither connector's shell receives the insert of the mating connector. Thus, “male” and “female” designations as used herein are assigned by preference of the inventor for differentiating between complementary connectors in a connector pair. The terms are not meant to be used in any limiting manner.
Other connector gender designations are also used in the electrical connector field, for instance the terms “plug” and “receptacle.” As colloquially used, the insert of a “plug” is received into the shell of a “receptacle.” Both plugs and receptacles are known in the art to have pins, sockets or a combination of pins and sockets. However, the “plug” and “receptacle” terminology is also subject to alternative meanings. For instance, “plug” is also defined as a connector which is designed to terminate a free end of a cable or cord, and “receptacle” is defined as a connector which is fixed to a bulkhead, wall, chassis, or panel. In other words, the “plug” is the movable connector and the “receptacle” is the fixed connector, regardless of which insert is received into which shell or which connector has pin contacts, socket contacts, etc. Using the latter terminology, when two cables are joined, the “plug-style” connector is often referred to as a “plug” and the “cable-connecting-receptacle-style connector” is often referred to as a “cable connecting plug.” Notwithstanding the above definitions, as used herein, the term “plug” simply refers to that portion of a connector insert which is received into the shell of the other, and the term “receptacle” simply refers to that portion of a connector shell which receives the insert of the other.
When there is a requirement for joining electrical conductors or optical fibers that are to be deployed under water or in humid environments, it is preferable to use connectors that are constructed in such a manner as to offer ease of mating and waterproof integrity. An O-ring, gasket, or packing is typically used to seal the cable end of a connector when repairability or modifiability is a required feature. Alternatively, the connector may be potted, adhesively bonded, or overmolded to create a seal between the cable jacket and the connector if re-entry is not required. However, sealing the interface between two mated connectors has traditionally been limited to the use of gaskets or O-rings which are compressed so that they conform to adjacent surfaces, thereby creating a fluid-proof barrier or seal which can be repeatedly mated and unmated.
The common interface between two connectors is most often sealed by only one sealing element, which is compressively engaged to effect the seal. The sealing element may be a separate and discreet piece which makes up the connector, or it may be an integral part of a unitary molded connector. A connector pair having only one interface sealing element provides no sealing redundancy, so that a defective seal at the connector interface is likely to destroy the integrity of the connection.
To provide redundancy, some waterproof or moisture-resistant connector pairs employ two interface sealing elements disposed on a portion of a connector insert. For example, FIG. 1 shows two sealing elements (9, 10) disposed on a plug (12) of a male connector (8) which is bonded to a cable (13). The compliant seals (9, 10) may be raised ridges integrally bonded to the connector insert, or they may be separate members, such as O-rings which are seated in O-ring grooves. FIG. 1 also depicts a prior art female connector (I) bonded to a cable (2). The male connector (8) is structured to mate with the female connector (1). The entire body of the female connector (1) and the entire body of the male connector (8) each commonly consists of a single molding of an elastomeric material such as rubber or polyurethane. The female connector (1) includes a shell (6) defining a barrel-shaped receptacle (5), and the male connector (8) includes an insert (14) defining a cylinder-shaped plug (12) which is designed and arranged to be inserted into the receptacle (5). The diameter of the plug (12) may be slightly larger than the inside diameter of the receptacle (5), provided the shell (6) of the female connector is made of a conformal material.
The female connector (1) of prior art is illustrated in FIG. 1 with a contact socket (7) that is electrically coupled to a conductor in the cable (2). The male connector (8) correspondingly includes a contact pin (11) that is electrically coupled to a conductor in the cable (13). The contact pin (11) has a diameter, shape and length required to correctly mate with the contact socket (7). Although the female connector is illustrated with a socket contact, it may alternatively have a pin contact, and the male connector may have a corresponding socket contact. Additionally, even though only one pin/socket arrangement is illustrated in FIG. 1, multiple pin and sockets are often used to couple multiple conductors.
As shown in FIG. 1, the cylindrical plug (12) of the male connector (8) of prior art has either two O-rings (each housed within an O-ring groove) or two integral and compliant coaxial protuberances (9, 10) disposed around the plug circumference. The protuberances (9, 10) have a generally cross-sectional hemispheric shape and emulate O-rings in both form and function. The barrel-shaped receptacle (5) of the female connector (1) includes on its interior side surface two coaxial grooves (3, 4) each having a generally cross-sectional hemispheric form. The grooves (3, 4) are designed and arranged to form O-ring grooves for receiving O-rings or protruding ridges (9, 10) while maintaining the compliant sealing elements (9, 10) in compression.
As illustrated in FIG. 1, the prior art connector pairs that feature redundant seals are known to have the sealing elements arranged such that in the process of mating the connector pair, both of the sealing elements (9, 10) do not engage simultaneously. The first distal sealing element (10) (with respect to the cable (13)) is positioned in tandem with the second proximal sealing element (9) so that the first must be engaged, i.e. compressed, before the second sealing element can be engaged. Referring to FIG. 1, the sequence of events during the mating operation is as follows: First, the plug (12) of the male connector (8) is inserted into the receptacle (5) of the female connector (1) until the pin (11) begins to engage its respective socket (7). Next, the penetration continues until the distal sealing ridge (10) is received into receptacle (5) and is finally seated in the distal groove (4) (with respect to the cable (2)). As the penetration continues, the distal sealing ridge (10) disengages from the distal groove (4) and moves to and engages with the proximal groove (3). Simultaneously, the proximal protuberance (9) engages the distal groove (4). In other words, in the process of mating a connector pair, the connector pair must pass over one seal before reaching the final sealing position during the mating operation.
When the distal sealing ridge (10) is disposed within the receptacle (5) but is not engaged in either groove (3) or (4), it is significantly deformed by compression. Because it requires more force to move one connector relative to other when a sealing element is significantly compressed therebetween, it is more difficult for one to mate the connector pair. Hence, operators become accustomed to applying a greater force to mate redundantly-sealed connectors then is customary for mating single-seal connectors, thereby increasing the likelihood of damaging one or more contact pins. If the connectors are initially misaligned, then the operator may not tactilely recognize the misalignment and instead apply too great a force, in turn bending one or more pins. Furthermore, with the prior art connector pair of FIG. 1, it is more difficult for the operator to tactilely feel if both sealing elements have engaged or whether only one sealing element has engaged.
3. Identification of Objects of the Invention
The primary object of the invention is to overcome and correct the aforementioned problems associated with the prior art by providing a connector pair having dual sealing elements at the connector interface that first engage simultaneously.
Another object of the invention is to provide a connector pair which promotes a tactile indication to an operator that the connection between the connector pair is complete and correct.
Another object of the invention is to provide a connector pair with improved waterproof or moisture-resistant characteristics.
Another object of the invention is to provide a connector pair with redundant seals which minimize the force required to mate the connectors.
Another object of the invention is to provide a connector pair which minimize the potential for bending or breaking contacts during the mating process.